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Abstract:

A server and a terminal enabling channel capacity estimation in a
High-Speed Downlink Packet Access (HSDPA) network and a method of
controlling the server and the terminal are provided. More particularly,
when transmitting data between both terminals in an HSDPA network, a
server end may transmit a packet pair of the same size and a client end
may measure a time difference between the packet pair and thereby proceed
filtering. Through this, it is possible to estimate the channel capacity.
Therefore, it is possible to prevent data transmission from exceeding the
channel capacity in the HSDPA to thereby prevent a packet loss and to
effectively use a channel.

Claims:

1. A method of controlling a terminal enabling channel capacity estimation
in a High-Speed Downlink Packet Access (HSDPA) network,
comprising:receiving two packets of the same size that are consecutively
transmitted via a channel without causing time latency;measuring a
received time difference between the two packets;dividing the length of
any one packet of the two packets by the time difference to calculate a
channel capacity value;calculating an average channel capacity value
based on a plurality of channel capacity values; andestimating the
channel capacity based on a plurality of average channel capacity values.

2. The method of claim 1, further comprising:filtering a channel capacity
value greater than a maximum data throughput per second in the HSDPA
network, among the plurality of channel capacity values.

3. The method of claim 2, wherein the maximum data throughput per second
is 1.8 Mbps.

4. A method of controlling a server enabling channel capacity estimation
in an HSDPA network, comprising:consecutively transmitting two packets of
the same size via a channel without causing time latency;receiving, from
a terminal that receives the two packets, information associated with a
time difference between the two received packets;dividing the length of
any one packet of the two packets by the time difference to calculate a
channel capacity value;calculating an average channel capacity value
based on a plurality of channel capacity values; andestimating the
channel capacity based on a plurality of average channel capacity values.

5. The method of claim 4, further comprising:filtering a channel capacity
value greater than a maximum data throughput per second in the HSDPA
network, among the plurality of channel capacity values.

6. The method of claim 4, wherein the maximum data throughput per second
is 1.8 Mbps.

7. A terminal enabling channel capacity estimation in an HSDPA network,
comprising:a receiver configured to receive two packets of the same size
that are consecutively transmitted via a channel without causing time
latency;a time difference measuring unit configured to measure a received
time difference between the two received packets;a channel capacity
calculator configured to divide the length of any one packet of the two
packets by the time difference and thereby calculate a channel capacity
value, and to calculate an average channel capacity value based on a
plurality of channel capacity values; anda channel capacity estimator
configured to estimate the channel capacity based on a plurality of
average channel capacity values.

8. The terminal of claim 7, further comprising:a filter configured to
filter a channel capacity value greater than a maximum data throughput
per second in the HSDPA network, among the plurality of channel capacity
values.

9. A server enabling channel capacity estimation in an HSDPA network,
comprising:a transmitter configured to consecutively transmit two packets
of the same size via a channel without causing time latency;a receiver
configured to receive, from a terminal that receives the two packets,
information associated with a time difference between the two received
packets;a channel capacity calculator configured to divide the length of
any one packet of the two packets by the time difference and thereby
calculate a channel capacity value, and to calculate an average channel
capacity value based on a plurality of channel capacity values; anda
channel capacity estimator configured to estimate the channel capacity
based on a plurality of average channel capacity values.

10. The server of claim 9, further comprising:a filter configured to
filter a channel capacity value greater than a maximum data throughput
per second in the HSDPA network, among the plurality of channel capacity
values.

Description:

TECHNICAL FIELD

[0001]The present invention relates to a server and a terminal enabling
channel capacity estimation in a High-Speed Downlink Packet Access
(HSDPA) network and a method of controlling the server and the terminal.
More particularly, the present invention relates to a channel capacity
estimation method and system in an HSDPA network in which a client end
may estimate the capacity of a current channel using a data packet
transmitted from a server end of an HSDPA network.

[0002]This work was supported by the IT R&D program of MIC/IITA.
[2005-S-103-03, Development of Ubiquitous Access Technology for
Convergence of Broadcasting and Communications]

[0004]In the HSDPA network, when data communication is being performed
between both terminals, a current channel capacity should be verified in
order to prevent packet loss that may occur due to exceeding of the
channel capacity and to effectively use a channel.

[0005]In the case of a channel capacity estimation algorithm between both
terminals in an existing Internet Protocol (IP) network, a server end may
transmit a data packet and an additional probing packet. A client end may
receive the probing packet and analyze the received probing packet.
Therefore, the channel capacity estimation algorithm may be used to
estimate the channel capacity in a wired IP network with a relatively
greater bandwidth in comparison to a wireless network.

[0006]In the channel capacity estimation algorithm, the additional probing
packets use a channel in the wireless network with a less channel
capacity, which results in reducing an available channel capacity of an
actual data packet.

DISCLOSURE OF INVENTION

Technical Problem

[0007]An aspect of the present invention provides a channel capacity
estimation method and system in a High-Speed Downlink Packet Access
(HSDPA) network in which a server end may transmit a pair of data packets
of the same size and filter the data packets appropriate for an HSDPA
network, and a client end can receive the data packets, measure a time
difference between the received data packets, and thereby estimate the
channel capacity, in order to obtain the channel capacity between both
terminals in the HSDPA network.

Technical Solution

[0008]According to an aspect of the present invention, there is provided a
method of controlling a terminal enabling channel capacity estimation in
a High-Speed Downlink Packet Access (HSDPA) network, including: receiving
two packets of the same size that are consecutively transmitted via a
channel without causing time latency; measuring a received time
difference between the two packets; dividing the length of any one packet
of the two packets by the time difference to calculate a channel capacity
value; calculating an average channel capacity value based on a plurality
of channel capacity values; and estimating the channel capacity based on
a plurality of average channel capacity values.

[0009]In this instance, the method may further include filtering a channel
capacity value greater than a maximum data throughput per second in the
HSDPA network, among the plurality of channel capacity values.

[0010]Also, the maximum data throughput per second may be 1.8 Mbps.

[0011]According to another aspect of the present invention, there is
provided a method of controlling a server enabling channel capacity
estimation in an HSDPA network, including: consecutively transmitting two
packets of the same size via a channel without causing time latency;
receiving, from a terminal that receives the two packets, information
associated with a time difference between the two received packets;
dividing the length of any one packet of the two packets by the time
difference to calculate a channel capacity value; calculating an average
channel capacity value based on a plurality of channel capacity values;
and estimating the channel capacity based on a plurality of average
channel capacity values.

[0012]In this instance, the method may further include filtering a channel
capacity value greater than a maximum data throughput per second in the
HSDPA network, among the plurality of channel capacity values.

[0013]According to still another aspect of the present invention, there is
provided a terminal enabling channel capacity estimation in an HSDPA
network, including: a receiver configured to receive two packets of the
same size that are consecutively transmitted via a channel without
causing time latency; a time difference measuring unit configured to
measure a received time difference between the two received packets; a
channel capacity calculator configured to divide the length of any one
packet of the two packets by the time difference and thereby calculate a
channel capacity value, and to calculate an average channel capacity
value based on a plurality of channel capacity values; and a channel
capacity estimator configured to estimate the channel capacity based on a
plurality of average channel capacity values.

[0014]In this instance, the terminal may further include a filter
configured to filter a channel capacity value greater than a maximum data
throughput per second in the HSDPA network, among the plurality of
channel capacity values.

[0015]According to yet another aspect of the present invention, there is
provided a server enabling channel capacity estimation in an HSDPA
network, including: a transmitter configured to consecutively transmit
two packets of the same size via a channel without causing time latency;
a receiver configured to receive, from a terminal that receives the two
packets, information associated with a time difference between the two
received packets; a channel capacity calculator configured to divide the
length of any one packet of the two packets by the time difference and
thereby calculate a channel capacity value, and to calculate an average
channel capacity value based on a plurality of channel capacity values;
and a channel capacity estimator configured to estimate the channel
capacity based on a plurality of average channel capacity values.

[0016]In this instance, the server may further include a filter configured
to filter a channel capacity value greater than a maximum data throughput
per second in the HSDPA network, among the plurality of channel capacity
values.

BRIEF DESCRIPTION OF THE DRAWINGS

[0017]FIG. 1 illustrates an example of channel capacity estimation
according to an embodiment of the present invention;

[0018]FIG. 2 is a block diagram illustrating a configuration of a terminal
enabling channel capacity estimation in a High-Speed Downlink Packet
Access (HSDPA) network according to an embodiment of the present
invention;

[0019]FIG. 3 is a block diagram illustrating a configuration of a server
enabling channel capacity estimation in an HSDPA network according to an
embodiment of the present invention;

[0020]FIG. 4 is a graph illustrating an experimental result for channel
capacity estimation in an HSDPA network according to an embodiment of the
present invention;

[0021]FIG. 5 is a graph illustrating an example of a linear model of
channel capacity estimation according to an embodiment of the present
invention;

[0022]FIG. 6 is a graph illustrating an example of an index model of
channel capacity estimation according to an embodiment of the present
invention;

[0023]FIG. 7 is a table illustrating the estimated channel capacity and an
error thereof according to an embodiment of the present invention;

[0024]FIG. 8 is a flowchart illustrating a method of controlling a server
enabling channel capacity estimation in an HSDPA network according to an
embodiment of the present invention; and

[0025]FIG. 9 is a flowchart illustrating a method of controlling a
terminal enabling channel capacity estimation in an HSDPA network
according to an embodiment of the present invention.

MODE FOR THE INVENTION

[0026]Reference will now be made in detail to embodiments of the present
invention, examples of which are illustrated in the accompanying
drawings, wherein like reference numerals refer to the like elements
throughout. The embodiments are described below in order to explain the
present invention by referring to the figures.

[0027]FIG. 1 illustrates an example of channel capacity estimation
according to an embodiment of the present invention. The channel capacity
may be measured using a packet pair in a wired Internet Protocol (IP)
network.

[0028]As shown in FIG. 1, in the wired IP network, when j+1 sections 130
with channel capacity, Co, . . . , Cj, exist and a section with
the minimum channel capacity is Cmin, a server end 110 may transmit
a packet pair 120 without time interval. A client end 140 may receive the
packet pair 120 and obtain a time difference ti 150 between the
packet pair.

[0029]When using the above-described packet pair probing technique, the
minimum channel capacity Cmin may be obtained in some section
between the server end 110 and the client end 140.

[0030]In a general wireless communication, a section with the least
channel capacity is a wireless section between a base station and a
terminal rather than a wired section on the Internet. Therefore, in a
High-Speed Downlink Packet Access (HSDPA) network, a section between a
base station and an HSDPA terminal may have the least channel capacity.

[0031]The least channel capacity Cimin in the wired IP network
that is obtained from the received packet pair 120 may be calculated
according to,

Cimin=Li/ti, [Equation 1]

[0032]where Li denotes the length of any one packet of the received
packet pair 120.

[0033]When using Equation 1, it is possible to estimate the least channel
capacity between the server and the terminal in the HSDPA network.

[0034]In the commercialized HSDPA network, the logical maximum data
throughput per second is 1.8 Mbps. Therefore, it is possible to filter a
channel capacity value greater than 1.8 Mbps among all the calculated
channel capacity values using Equation 1 and thereby remove the channel
capacity value.

[0035]When the server end 110 transmits a total of `N` packets and in this
instance, the average channel capacity value is `E`, the estimated
channel capacity CEstimated may be calculated according to,

[0038]FIG. 2 is a block diagram illustrating a configuration of a terminal
140 enabling channel capacity estimation in an HSDPA network according to
an embodiment of the present invention.

[0039]As shown in FIG. 2, the terminal 140 includes a receiver 210, a time
difference measuring unit 220, a filter 230, a channel capacity
calculator 240, and a channel capacity estimator 250.

[0040]The receiver 210 may receive two packets of the same size that are
consecutively transmitted via a channel without causing time latency.

[0041]The time difference measuring unit 220 may measure a time difference
between the two received packets.

[0042]The filter 230 may filter a channel capacity value greater than a
maximum data throughput per second in the HSDPA network, among a
plurality of channel capacity values. Based on that the maximum data
throughput per second is 1.8 Mbps, the filter 230 may filter and remove
the channel capacity value greater than 1.8 Mbps.

[0043]The channel capacity calculator 240 may divide the length of any one
packet of the two packets by the time difference and thereby calculate a
channel capacity value. Also, the channel capacity calculator 240 may
calculate an average channel capacity value based on a plurality of
channel capacity values.

[0044]The channel capacity estimator 250 may estimate the channel capacity
based on a plurality of average channel capacity values.

[0045]FIG. 3 is a block diagram illustrating a configuration of a server
110 enabling channel capacity estimation in an HSDPA network according to
an embodiment of the present invention. Hereinafter, the server 110 will
be described with reference to FIG. 3.

[0046]As shown in FIG. 3, the server 110 includes a transmitter 310, a
receiver 320, a filter 330, a channel capacity calculator 340, and a
channel capacity estimator 350.

[0047]The transmitter 310 may consecutively transmit two packets of the
same size via a channel without causing time latency.

[0048]The receiver 320 may receive information associated with a time
difference between the two received packets from a terminal that receives
the two packets.

[0049]The filter 330 may filter a channel capacity value greater than a
maximum data throughput per second in the HSDPA network, among a
plurality of channel capacity values. Based on that the maximum data
throughput per second is 1.8 Mbps, the filter 330 may filter and remove
the channel capacity value greater than 1.8 Mbps.

[0050]The channel capacity calculator 340 may divide the length of any one
packet of the two packets by the time difference and thereby calculate a
channel capacity value. The channel capacity calculator 340 may calculate
an average channel capacity value based on a plurality of channel
capacity values.

[0051]The channel capacity estimator 350 may estimate the channel capacity
based on a plurality of average channel capacity values.

[0052]FIG. 4 is a graph illustrating an experimental result for channel
capacity estimation in an HSDPA network according to an embodiment of the
present invention. Specifically, FIG. 4 illustrates the actual
experimental result for obtaining Equation 2 and Equation 3.

[0053]In FIG. 4, the horizontal axis denotes the average channel capacity
value E that is obtained after filtering. The vertical axis denotes the
actual channel capacity in the HSDPA network.

[0054]When obtaining a linear model of Equation 2 and an index model of
Equation 3 from data of FIG. 4, they may be respectively given by,

CEstimated=1.5955×E-560.35 (Kbps),E>380 (Kbps), [Equation
4]

CEstimated=0.125×E (Kbps),E<380 (Kbps)

CEstimated=62.469e0.0029E (Kbps). [Equation 5]

[0055]When using Equation 4 or Equation 5, it is possible to estimate the
channel capacity CEstimated.

[0056]FIG. 5 is a graph illustrating an example of a linear model of
channel capacity estimation according to an embodiment of the present
invention, and FIG. 6 is a graph illustrating an example of an index
model of channel capacity estimation according to an embodiment of the
present invention.

[0057]FIG. 5 represents Equation 4 as a graph. FIG. 6 represents Equation
5 as a graph. Specifically, it is possible to more appropriately induce
the linear model of Equation 2 and the index model of Equation 3 from
data of FIG. 4.

[0058]FIG. 7 is a table 700 illustrating the estimated channel capacity
and an error thereof according to an embodiment of the present invention.
Specifically, the table 700 includes an average channel capacity value E
710 using packet pair probing technique, a measured actual capacity value
720, an estimated channel capacity value 730, and an error between the
measured actual capacity value 720 and the estimated channel capacity
value 730.

[0060]As shown in the table 700, the error between the measured actual
capacity value 720 and the estimated channel capacity value 730 may be a
maximum of about 90 Kbps. Therefore, it is possible to estimate the
channel capacity within the error range to thereby transmit data.

[0061]FIG. 8 is a flowchart illustrating a method of controlling a
terminal enabling channel capacity estimation in an HSDPA network
according to an embodiment of the present invention. Hereinafter, the
controlling method of the terminal according to an embodiment of the
present invention will be described with reference to FIG. 8.

[0062]In operation 5810, the method may receive two packets of the same
size that are consecutively transmitted via a channel without causing
time latency. In operation 5820, the method may measure a time difference
between the two received packets.

[0063]In operation 5830, the method may divide the length of any one
packet of the two packets by the time difference to calculate a channel
capacity value.

[0064]In operation 5840, the method may filter a channel capacity value
greater than a maximum data throughput per second in the HSDPA network,
among a plurality of channel capacity values. According to an aspect of
the present invention, it is possible to filter and remove the exceeding
maximum data throughput per second based on 1.8 Mbps.

[0065]In operation 5850, the method may calculate an average channel
capacity value based on a plurality of channel capacity values.

[0066]In operation 5860, the method may estimate the channel capacity
based on a plurality of average channel capacity values.

[0067]FIG. 9 is a flowchart illustrating a method of controlling a server
enabling channel capacity estimation in an HSDPA network according to an
embodiment of the present invention. Hereinafter, the controlling of the
terminal will be described with reference to FIG. 9.

[0068]In operation 5910, the method may consecutively transmit two packets
of the same size via a channel without causing time latency.

[0069]In operation 5920, the method may receive, from a terminal that
receives the two packets, information associated with a time difference
between the two received packets.

[0070]In operation 5930, the method may divide the length of any one
packet of the two packets by the time difference to calculate a channel
capacity value.

[0071]In operation 5940, the method may filter a channel capacity value
greater than a maximum data throughput per second in the HSDPA network,
among a plurality of channel capacity values. According to an aspect of
the present invention, it is possible to filter and remove the exceeding
maximum data throughput per second based on 1.8 Mbps.

[0072]In operation 5950, the method may calculate an average channel
capacity value based on a plurality of channel capacity values.

[0073]In operation 5960, the method may estimate the channel capacity
based on a plurality of average channel capacity values.

[0074]According to the present invention, it is possible to estimate the
channel capacity between both terminals in an HSDPA network. Therefore,
it is possible to prevent data transmission from exceeding the channel
capacity in the HSDPA to thereby prevent a packet loss and to effectively
use a channel.

[0075]Although a few embodiments of the present invention have been shown
and described, the present invention is not limited to the described
embodiments. Instead, it would be appreciated by those skilled in the art
that changes may be made to these embodiments without departing from the
principles and spirit of the invention, the scope of which is defined by
the claims and their equivalents.

Patent applications by Hye Soo Kim, Seoul KR

Patent applications by Jeong Ju Yoo, Daejeon KR

Patent applications by Jin Woo Hong, Daejeon KR

Patent applications by Seong-Jun Bae, Daejeon KR

Patent applications by Sung Jea Ko, Seoul KR

Patent applications by Electronics and Telecommunications Research Institute